With the evolution of optoelectronics and semiconductor technology, it has also driven the flourishing development of Flat Panel Display. In many flat panel displays, thin film transistor liquid crystal displays (TFT-LCDs) have become the mainstream of the market due to their advantages of high space utilization efficiency, low power consumption, no radiation and low electromagnetic interference.
Oxide semiconductor materials, such as Indium Gallium Zinc Oxide (IGZO), are widely used in thin film transistor devices for the display industry due to their high mobility and on-state current. However, the process of the commonly used bottom-gate IGZO TFT is complicated and an etching-stop-layer (ESL) needs to be added in order to prevent the IGZO at the channel from being damaged when the source/drain metal electrode layer is wet-etched to affect device performance. However, the fabrication of the ESL increases the complexity of the fabrication process and is not conducive to cost reduction.